FreshValueGenerator generator = new FreshValueGenerator();
    T instance = generator.newFreshProxy(interfaceType);
    new EqualsTester()
        .addEqualityGroup(wrapperFunction.apply(instance), wrapperFunction.apply(instance))
        .addEqualityGroup(wrapperFunction.apply(generator.newFreshProxy(interfaceType)))
        // TODO: add an overload to EqualsTester to print custom error message?
        .testEquals();
  }

   *     or if the hashcodes are different.
   */
  @CanIgnoreReturnValue
  public static <T> T reserializeAndAssert(T object) {
    T copy = reserialize(object);
    new EqualsTester().addEqualityGroup(object, copy).testEquals();
    Assert.assertEquals(object.getClass(), copy.getClass());
    return copy;
  }

    differentTypes.put(Range.closedOpen(3.0, 4.0), 2);
    new EqualsTester()
        .addEqualityGroup(empty, TreeRangeMap.<Integer, Integer>create())
        .addEqualityGroup(nonEmpty, coalesced)
        .addEqualityGroup(differentValues)
        .addEqualityGroup(differentTypes)
        .testEquals();
  }

  private void verify(Map<Integer, Integer> model, RangeMap<Integer, Integer> test) {

    assertThrows(IllegalArgumentException.class, () -> ContiguousSet.closedOpen(2L, 1L));
  }

  public void testEquals() {
    new EqualsTester()
        .addEqualityGroup(
            ContiguousSet.create(Range.closed(1, 3), integers()),
            ContiguousSet.closed(1, 3),
            ContiguousSet.create(Range.closedOpen(1, 4), integers()),
            ContiguousSet.closedOpen(1, 4),

    MapDifference<Integer, String> diff2 = Maps.difference(left, right2);

    new EqualsTester()
        .addEqualityGroup(original, same)
        .addEqualityGroup(reverse)
        .addEqualityGroup(diff2)
        .testEquals();
  }

  public void testMapDifferencePredicateTypical() {

                .put("foo", 3)
                .put("foo", 1)
                .build())
        .addEqualityGroup(
            ImmutableSetMultimap.<String, Integer>builder()
                .put("foo", 2)
                .put("foo", 3)
                .put("foo", 1)
                .build())
        .addEqualityGroup(
            ImmutableSetMultimap.<String, Integer>builder().put("bar", 2).put("foo", 3).build())

   *     or if the hashcodes are different.
   */
  @CanIgnoreReturnValue
  public static <T> T reserializeAndAssert(T object) {
    T copy = reserialize(object);
    new EqualsTester().addEqualityGroup(object, copy).testEquals();
    Assert.assertEquals(object.getClass(), copy.getClass());
    return copy;
  }

    assertThrows(IllegalArgumentException.class, () -> ContiguousSet.closedOpen(2L, 1L));
  }

  public void testEquals() {
    new EqualsTester()
        .addEqualityGroup(
            ContiguousSet.create(Range.closed(1, 3), integers()),
            ContiguousSet.closed(1, 3),
            ContiguousSet.create(Range.closedOpen(1, 4), integers()),
            ContiguousSet.closedOpen(1, 4),

  @After
  public void validateUndirectedEdges() {
    for (Integer node : network.nodes()) {
      new EqualsTester()
          .addEqualityGroup(
              network.inEdges(node), network.outEdges(node), network.incidentEdges(node))
          .testEquals();
      new EqualsTester()
          .addEqualityGroup(
              network.predecessors(node), network.successors(node), network.adjacentNodes(node))
          .testEquals();

  @After
  public void validateUndirectedEdges() {
    for (Integer node : network.nodes()) {
      new EqualsTester()
          .addEqualityGroup(
              network.inEdges(node), network.outEdges(node), network.incidentEdges(node))
          .testEquals();
      new EqualsTester()
          .addEqualityGroup(
              network.predecessors(node), network.successors(node), network.adjacentNodes(node))
          .testEquals();